Area and Circumference of a Circle

Front

What is the formula for the circumference of a circle?

Back

Circumference = 2 × π × radius or Circumference = π × diameter.

Front

What is the value of π (pi) approximately?

Back

π (pi) is approximately 3.14.

Front

If a circle has a radius of 5 inches, what is its circumference?

Back

Circumference = 2 × π × 5 = 31.4 inches.

Front

What is the formula for the area of a circle?

Back

Area = π × radius².

Front

If a circle has a radius of 3 inches, what is its area?

Back

Area = π × 3² = 28.26 square inches.

Front

What is the relationship between diameter and radius?

Back

Diameter = 2 × radius.

Front

If the diameter of a circle is 10 inches, what is its radius?

Back

Radius = diameter ÷ 2 = 10 ÷ 2 = 5 inches.

Front

What is the circumference of a circle with a diameter of 12 inches?

Back

Circumference = π × 12 = 37.68 inches.

Front

How do you convert radius to diameter?

Back

Multiply the radius by 2.

Front

What is the area of a circle with a radius of 4 inches?

Back

Area = π × 4² = 50.24 square inches.